﻿
using System;

using System.Collections.Generic;

using System.Text;

using System.Web;

using System.Configuration;

using System.Data;

using System.Data.SQLite;



namespace SQLiteHelp
{

    public class SQLiteHelper
    {

        /// <summary>

        /// 获得连接对象

        /// </summary>

        /// <returns></returns>

        public static SQLiteConnection GetSQLiteConnection()
        {

            return new SQLiteConnection(@"Data Source=|DataDirectory|\TenyDB.db;Version=3");

        }



        private static void PrepareCommand(SQLiteCommand cmd, SQLiteConnection conn, string cmdText, params object[] p)
        {



            if (conn.State != ConnectionState.Open)

                conn.Open();

            cmd.Parameters.Clear();

            cmd.Connection = conn;

            cmd.CommandText = cmdText;



            cmd.CommandType = CommandType.Text;

            cmd.CommandTimeout = 30;



            if (p != null)
            {

                foreach (object parm in p)

                    cmd.Parameters.AddWithValue(string.Empty, parm);

                //for (int i = 0; i < p.Length; i++)

                //    cmd.Parameters[i].Value = p[i];

            }

        }



        public static DataSet ExecuteDataset(string cmdText, params object[] p)
        {

            DataSet ds = new DataSet();

            SQLiteCommand command = new SQLiteCommand();

            using (SQLiteConnection connection = GetSQLiteConnection())
            {

                PrepareCommand(command, connection, cmdText, p);

                SQLiteDataAdapter da = new SQLiteDataAdapter(command);

                da.Fill(ds);

            }



            return ds;

        }



        public static DataRow ExecuteDataRow(string cmdText, params object[] p)
        {

            DataSet ds = ExecuteDataset(cmdText, p);

            if (ds != null && ds.Tables.Count > 0 && ds.Tables[0].Rows.Count > 0)

                return ds.Tables[0].Rows[0];

            return null;

        }



        /// <summary>

        /// 返回受影响的行数

        /// </summary>

        /// <param name="cmdText">a</param>

        /// <param name="commandParameters">传入的参数</param>

        /// <returns></returns>

        public static int ExecuteNonQuery(string cmdText, params object[] p)
        {

            SQLiteCommand command = new SQLiteCommand();



            using (SQLiteConnection connection = GetSQLiteConnection())
            {

                PrepareCommand(command, connection, cmdText, p);

                return command.ExecuteNonQuery();

            }

        }



        /// <summary>

        /// 返回SqlDataReader对象

        /// </summary>

        /// <param name="cmdText"></param>

        /// <param name="commandParameters">传入的参数</param>

        /// <returns></returns>

        public static SQLiteDataReader ExecuteReader(string cmdText, params object[] p)
        {

            SQLiteCommand command = new SQLiteCommand();

            SQLiteConnection connection = GetSQLiteConnection();

            try
            {

                PrepareCommand(command, connection, cmdText, p);

                SQLiteDataReader reader = command.ExecuteReader(CommandBehavior.CloseConnection);

                return reader;

            }

            catch
            {

                connection.Close();

                throw;

            }

        }



        /// <summary>

        /// 返回结果集中的第一行第一列，忽略其他行或列

        /// </summary>

        /// <param name="cmdText"></param>

        /// <param name="commandParameters">传入的参数</param>

        /// <returns></returns>

        public static object ExecuteScalar(string cmdText, params object[] p)
        {

            SQLiteCommand cmd = new SQLiteCommand();



            using (SQLiteConnection connection = GetSQLiteConnection())
            {

                PrepareCommand(cmd, connection, cmdText, p);

                return cmd.ExecuteScalar();

            }

        }



        /// <summary>

        /// 分页

        /// </summary>

        /// <param name="recordCount"></param>

        /// <param name="pageIndex"></param>

        /// <param name="pageSize"></param>

        /// <param name="cmdText"></param>

        /// <param name="countText"></param>

        /// <param name="p"></param>

        /// <returns></returns>

        public static DataSet ExecutePager(ref int recordCount, int pageIndex, int pageSize, string cmdText, string countText, params object[] p)
        {

            if (recordCount < 0)

                recordCount = int.Parse(ExecuteScalar(countText, p).ToString());



            DataSet ds = new DataSet();



            SQLiteCommand command = new SQLiteCommand();

            using (SQLiteConnection connection = GetSQLiteConnection())
            {

                PrepareCommand(command, connection, cmdText, p);

                SQLiteDataAdapter da = new SQLiteDataAdapter(command);

                da.Fill(ds, (pageIndex - 1) * pageSize, pageSize, "result");

            }

            return ds;

        }

    }

}
 
